An Investigation of the Freeway Space and Facial Proportions in Dentate Subjects

The purpose of this study was to measure the freeway space and facial height of dentate subjects. One hundred and fifty two dentate subjects with ages ranging from 17 to 30 years composed the sample. The freeway space was determined as the difference between rest vertical dimension and occlusal vertical dimension. The Willis gauge was used to measure upper and lower facial heights in resting. Data were collected by two independent observers. The measurements of the two independent observers were submitted to the Intra- Class Correlation test. Differences between upper and lower facial heights were compared with Student's t test (α = 0.05). The intraclass correlation index (ICC = 0.997, P < .0001) showed excellent reproducibility between the two observers. The freeway space of dentate subjects ranged from 1 to 7 mm. Mean upper facial height (53.7 ± 9.4 mm) and mean lower facial height (54.2 ± 9.9 mm) did not differ significantly. Since most volunteers presented a freeway space ranging from 2 to 4 mm (74%) and the upper facial height seemed to be equal to the lower facial height in resting, these values may be used as initial parameters for the reestablishment of the vertical dimension of occlusion.